Hydraulic crimping apparatus

ABSTRACT

An hydraulic crimper ( 1 ) comprising, an elongated crimping assembly ( 3 ) with a forward end and a rearward end the crimper assembly having a crimping head ( 11 ) moveable towards and away from a die ( 9 ), a handle ( 5 ) for holding the crimping assembly, the handle extending above the crimping assembly and being constructed so that it has a balanced position where it may be held with the hydraulic crimper in balance, an actuator ( 7 ) moveable between an on setting and an off setting, the actuator being located on the handle, a control valve ( 37 ) for controlling flow of hydraulic fluid under pressure to move the crimping head, and a mechanical linkage ( 13 ) extending from the actuator to the control valve whereby to control the movement of the crimping head in response to the setting of the actuator.

FIELD OF THE INVENTION

This invention relates to a crimper. It relates particularly but not exclusively to a hydraulic crimper which is suitable for crimping lugs and links associated with the assembly of high voltage cables.

BACKGROUND OF THE INVENTION

In the assembly of high voltage cable systems, lugs and links often need to be applied to high voltage cables which are strung high above the ground. Sometimes the cables even need to be repaired or adjusted when they are live.

In order to rapidly apply lugs or links to assist with repair or assembly of the cable, crimping tools are generally used. Because these crimping tools often need to be used by a workman operating in an elevated position, it is important that they be designed to operate rapidly and safely. Furthermore, they must be sufficiently light to enable a single operator to readily lift them into position for crimping. Typically, the weight of crimping devices should be no greater than about 9 kg. Their design must also facilitate easy handling and balancing. The devices should preferably be weighted in such a way that they can be lifted in place with one hand and operated by that same hand.

Currently there are a number of different types of crimping tools on the market. Of these there are two basic types which have the closest similarity to applicant's invention. One type is battery powered. It has the required balance and weight characteristics. However, it is relatively slow in operation because of the limitations inherent in using a battery powered supply. It also has a limited number of crimping cycles per battery charge.

The second basic type of crimping device is operated by an externally supplied source of hydraulic power which connects to the device through long hydraulic hoses. Because the device is associated with control systems for the hydraulic operation, it is configured in such a way that it is not readily balanced unless an operator uses both hands to hold it. This can be a significant disadvantage in the awkward situations encountered when crimping power lines at elevated locations.

Thus there is a need for a safe device which has the advantages of relatively light weight construction, rapid operation and a configuration which allows it to be relatively easily balanced and used.

DISCLOSURE OF THE INVENTION

The invention provides in one aspect a hydraulic crimper comprising,

-   -   an elongate crimping assembly having a crimping head moveable         towards and away from a die,     -   a handle for holding the crimping assembly, the handle extending         above the crimping assembly and being constructed so that it has         a balanced position where it may be held with the hydraulic         crimper in balance,     -   an actuator moveable between an on setting and an off setting,         the actuator being located on the handle,     -   a control valve for controlling flow of hydraulic fluid to move         the crimping head, and     -   a mechanical linkage extending from the actuator to the control         valve whereby to control the movement of the crimping head in         response to the setting of the actuator.

Suitably, the weight of the hydraulic crimper is less than 9 kg.

The elongate crimping assembly may have a forward end for holding the die and a rearward end. The rearward end may include a piston and cylinder for moving the crimping head.

The handle may be attached at or near the rearward end of the crimping assembly. It may extend above and parallel to the crimping assembly. It may include the control valve. The control valve may be housed in a housing connected to and forming an extension of the handle.

Suitably, the actuator is located at a forward end of the handle. It may be located so that it may be moveable by finger or thumb pressure when the handle is being held at the balance point. It may be arranged to pivot when depressed to move a push rod. The push rod may move the control valve to control the flow of hydraulic fluid and hence movement of the piston.

Suitably, the actuator is biased so that it assumes a position whereby the crimping head is away from the die when there is no finger pressure on the actuator. The control valve may comprise a housing and a spool moveable within the housing to control the flow of fluid. The spool may be moveable by the push rod. It may be biased by hydraulic pressure to assume a configuration whereby the crimping head is away from the die when there is no finger pressure on the actuator.

The control valve may be arranged to direct hydraulic fluid in front of and behind a piston in the piston chamber to move the crimping head away from and towards the die.

A secondary valve may be associated with the piston. The secondary valve may be arranged to control flow of hydraulic fluid from a forward part of the piston chamber to a rearward part thereof. It may be a poppet valve fitted in the piston.

Adjustment means may be provided in association with the poppet valve. The adjustment means may serve to allow the poppet valve to assume an open position or a closed position with regard to transfer of hydraulic fluid from the forward part of the piston chamber to the rearward part depending on its setting. When the piston is completely retracted so that the crimping head has been moved to the maximum extent away from the die the adjustment means may be set to open or close the poppet valve.

Ducting may be provided in the piston to allow transfer of hydraulic fluid from the forward part of the piston chamber to the rearward part. The poppet valve may operate to open and close the ducting to control flow of hydraulic fluid.

Alternatively the secondary valve may comprise an adjustable valve provided in the handle. It may be arranged to allow fluid to bypass the piston chamber when the piston is fully retracted. The secondary valve may comprise a spring loaded ball valve. Suitably the hydraulic crimper includes a facility to prevent excess hydraulic fluid pressure build up in the crimper. This may be achieved by incorporating a pressure relief valve in the construction.

Thus in another aspect the invention provides an hydraulic crimper comprising,

-   -   an elongate crimping head moveable towards and away from a die,     -   an actuator moveable between an on setting and an off setting,     -   a control valve for controlling flow of hydraulic fluid under         pressure to move the crimping head,     -   an inlet for the hydraulic fluid,     -   an outlet for the hydraulic fluid,     -   a mechanical linkage extending from the actuator to the control         valve whereby to control the movement of the crimping head in         response to the setting to the actuator,     -   an outlet duct for directing the hydraulic fluid from the         control valve to the outlet, and     -   a one way valve set to open and allow the hydraulic fluid to         pass through the inlet.

As it is also useful for an operator to be able to know when hydraulic fluid is flowing through, one or more sections of the crimper the crimper may include a sensor for signalling the passage of hydraulic fluid through a duct. The sensor may suitably be placed downstream of a pressure sensitive relief valve. It may be used as an indicator that the crimper has achieved the correct crimp force at the die.

Thus in another aspect the invention provides a sensor for signalling the passage of the hydraulic fluid through a duct comprising,

-   -   a flow member exposed to the movement of the hydraulic fluid         through the duct moveable in response to movement of the         hydraulic fluid through the duct, and     -   sensing means isolated from contact with the hydraulic fluid,         the sensing means being responsive to movement of the flow         member to provide a signal for indicating the passage of the         hydraulic fluid.

The sensor may comprise a paddle mounted for pivotal movement in response to the passage of the hydraulic fluid through the duct and the sensing means may comprise a chamber for housing and isolating a moveable, visible indicator member from the hydraulic fluid, and at least one of the paddle and visible indicator may include a permanent magnet to magnetically tie the movement of the visible indicator to respond to movement of the paddle.

The chamber may include a transparent window through which the visible indicator may be viewed and the paddle may be connected to resilient means to urge the paddle to a rest position in the absence of the hydraulic fluid moving through the duct.

In the absence of hydraulic pressure it is preferred that the hydraulic crimper include retraction means adapted to automatically retract the crimping head away from the die when the pressure of the hydraulic fluid falls below a predetermined limit.

The retraction means may comprise a spring telescoping a push rod connecting the piston and crimping head.

Preferred aspects of the invention will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of a hydraulic crimper according to the invention;

FIG. 2 shows an isometric view of the crimper of FIG. 1;

FIG. 3 shows a section A-A taken through the crimper of FIG. 1;

FIG. 4 shows an exploded view of the crimper of FIG. 1;

FIGS. 5 to 7 show a sequence of steps in the flow of hydraulic fluid through the crimper of FIG. 1 with the crimper being set in an open centre mode;

FIGS. 8 to 10 show a sequence of steps in the flow of hydraulic fluid through the crimper of FIG. 1 with the crimper being set in a closed centre mode;

FIG. 11 shows a plan view of an alternative hydraulic crimper according the invention;

FIG. 12 shows a section A-A taken through the crimper of FIG. 11;

FIG. 13 shows a section B-B taken through the crimper of FIG. 11;

FIG. 14 shows a section C-C taken through the crimper of FIG. 11;

FIG. 15 shows an exploded view of the crimper of FIG. 11;

FIGS. 16 to 18 show a sequence of steps in the flow of hydraulic fluid through the crimper of FIG. 11 with the crimper being set in an open centre mode; and

FIGS. 19 to 21 show a sequence of steps in the flow of hydraulic fluid through the crimper of FIG. 11 with the crimper being set in a closed centre mode.

The various integers identified by numerals in the drawings are listed in the “Integer List” attached to the end of this specification.

Referring to FIGS. 1 to 4, the hydraulic crimper generally designated 1 comprises an elongate crimping assembly 3 with a handle 5 attached at the rear of the crimping assembly. The handle is constructed so that it may be lifted with one hand with the crimping assembly in balance.

A depressible actuator 7 is provided on a forward part of the handle in a location where a person holding the handle with one hand may depress the actuator with the thumb of that hand. A push rod 13 attached at one end of the handle is arranged to push the control valve 37 in the direction of the left hand side of the page when the actuator 7 is depressed to cause it to pivot about the pivot 8 and hence push the push rod 13.

The general arrangement is such that depression of the actuator will ultimately cause the crimping head 11 to move towards the die 9 in response to the action of hydraulic pressure on a piston when the device is actuated. The crimping head 11 and die 9 may each be configured to receive and hold an insert to provide an adjustable crimp size.

The die 9 connects with the remainder of the crimping assembly with the crimping head 11 slidable within a bore forming part of the die.

A push rod 14 connects at one end to the crimping head 11 and the piston 21 at its other end the push rod being slidable within the bore 15.

The bore 15 is formed in the connecting member 17. The connecting member connects to the die 9 at one end and to the piston housing 25 which includes a cylindrical portion within which the piston may slide, at the other end. The connecting member and piston housing define a cylindrical piston chamber 23 between them. A screw 19 is used to attach the piston 21 to the push rod 14. In turn the crimping head connects to the other end of the push rod 14 by any suitable means such as a screw and thread arrangement. An O-ring seal may be provided between the push rod 14 and portion of the crimping head telescoping the push rod.

A number of screws 26, shown more clearly in FIG. 4, are used to attach the flared end of the connecting member 17 to the piston housing 25 to close off the piston chamber 23 in the manner illustrated.

A bore 27 is formed in a central portion of the piston 21. The bore is shaped to receive the collar 30 in which is mounted a poppet valve 29. The poppet valve is slidable within the collar to open and close the ducting 32 formed in the collar 30.

Ducting 31 in the piston is provided to allow fluid communication between the forward part of the piston chamber into the bore 27, through the duct 31 and into the gap 35 between the end of the piston and the end of the piston chamber when the poppet valve is in the open position.

A screw 33 mounted within a collar 34 is located so that it protrudes through the end wall of the piston housing 25 into the gap 35. The screw is adjustable so that it may be brought into contact with an end of the poppet valve to close off the duct 32 when the piston is in its most rearward position. Alternatively, if the screw 33 is in a retracted position, the poppet valve may assume an open configuration when the piston is in its most retracted position allowing communication of fluid between the forward part of the piston chamber and the gallery 35.

A relief valve 45 is provided in association with the handle mounting and control valve for purposes to become apparent.

Referring to FIGS. 5 to 7, the control valve 37 fits in the housing 39 forming part of the handle. The housing 39 is formed from the same billet as the piston housing 25. The control valve lies in a chamber 40 defined by the housing and is adjustable by movement of the push rod 13.

The control valve is arranged so that it controls the flow of hydraulic fluid such as oil from a pressure source through an inlet 58 through ducting to exit via the outlet 60. As shown in FIGS. 5 to 10 it controls the movement of the piston 21 within the piston chamber or cylinder 23. The inlet and outlet are provided at the rear of the crimper.

Control of the piston is achieved by movement of a spool 49 forming part of the control valve within the housing 47 also forming part of the control valve. The control valve operates by directing hydraulic fluid through the first and second ducts 41 and 43 to move the piston back and forth within the piston chamber/cylinder.

To control fluid flow, the housing 47 and spool 49 define a gallery 51 therebetween through which fluid may flow. The push rod 13 moves the spool with respect to the housing 47. This changes the path of flow of fluid through the gallery, through the opening 53 in the spool, and the openings 56 and 55 in the housing 47. Thus it can direct the fluid flow in the ducts 43, 41 and 59.

The rearward end 54 of the spool is arranged so that it may be moved backwards by the action of the push rod 13 to telescope into and seal off the end of a fixed collar 61 provided in the housing. This has the effect of sealing off the openings 55 and 56.

A spring 62 located within the collar is arranged to push against the rearward end 54 of the spool to return it to its “rest” configuration when finger pressure on the activator is released.

Taking a typical sequence of operations illustrated in FIGS. 5 to 7, when the actuator is not depressed it assumes the configuration shown in FIG. 3 and FIG. 5. In the particular configuration of FIG. 5, the screw 33 has been set in an extended position so that the poppet valve 29 is open when the piston is fully retracted in the piston chamber. Thus, when the device is not being used, the spring 62 urges the spool in the right hand direction to press against the push rod 13 and thereby lift the actuator into the upper configuration shown in FIG. 3.

In this setting, the spool and housing 47 create a gallery 51 around which oil from the inlet 58 may flow into the second duct 43 and hence the piston chamber 23 forward of the piston. From there the oil flows through the duct 32 past the poppet valve and into the gap 35. It exits via the first duct 41 back through the opening 55, the collar 61 and out the outlet 60 ie. in this configuration oil simply flows into and out of the device as long as hydraulic pressure is maintained. In the industry this is called an open centre valve setting.

When the actuator is depressed, the push rod 13 moves the spool to the left of the page, as is illustrated in FIG. 6, thereby closing off access of oil from the gallery 51 directly into the duct 43. This has the effect of shifting the flow of oil from the gallery so that it allows oil to flow into the openings 55 and 56 and hence the ducts 59 and 41.

As the duct 41 directs oil to the rear of the piston in the piston chamber the oil pressure at the rear of the piston as shown in FIG. 6 pushes the poppet valve closed and pushes the piston in the direction of the arrow thereby moving the crimping head towards the die.

When the piston is fully advanced as is shown in FIG. 7 and the actuator is held depressed, the oil pressure is relieved through the relief valve 45 allowing oil coming from the gallery 51 to pass through the opening 56 and duct 59 to the relief valve and hence to the outlet 60. The relief valve is set at a pressure to guarantee the full desired force is applied to the die. Typically the pressure would be about 1,500 to 2,000 psi.

When the actuator is released, the spring 62 urges the spool back to the configuration illustrated in FIG. 5 causing oil to flow through duct 43 into the piston chamber forward of the piston. This has the effect of causing the piston to retract to the configuration shown in FIG. 5. Oil then continuously flows through the poppet valve, through the duct 41 and ultimately out of the outlet 60.

The sequence shown in FIGS. 8 to 10 is with the same arrangement of components described with reference to FIGS. 5 to 7 with the exception that the screw 33 is retracted so that it does not open the poppet valve 29 when it is in the rest configuration shown in FIG. 8. This is called a closed centre valve setting.

In the rest configuration when the actuator is not depressed, oil flows through the gallery 51 from the inlet 58 into the duct 43 to fill the piston chamber 23 and pushes the piston back to the retracted position illustrated whilst at the same time pushing the poppet valve closed. Thus, there is no flow of oil into the gap 35 formed between the end of the piston and the back face of the piston chamber. As in the case of the corresponding FIG. 6, when the actuator is depressed, the control valve 37 directs oil through the duct 41 to push the piston forward, the pressure of oil also acting to close the poppet valve 29 as the piston moves forward to move the crimping head towards the die.

When the piston assumes the configuration shown in FIG. 10, the oil flow again is the same as that shown for FIG. 7 in that the relief valve acts to relieve oil pressure from the inlet 58 so that it may exit out the outlet after travelling through the relief valve and the area of the piston chamber in communication with the duct 41. Release of pressure on the actuator allows the spring 62 to return the device to the configuration shown in FIG. 8.

Referring to FIGS. 11 to 15, the alternative form of crimper shown therein differs from that previously described with reference to FIGS. 1 to 10 in four main aspects, namely:

-   -   (i) the valving for setting the device in the open/closed centre         mode is located at the rear end of the handle;     -   (ii) the device is set to automatically retract the crimper head         should hydraulic pressure fail for whatever reason;     -   (iii) a check valve is included in the ducting to prevent damage         and improve safety should hydraulic hoses be wrongly connected         in reverse to the inlet and outlet; and     -   (iv) a visual indicator is included to show when the pressure         relief valve is actuated in response to hydraulic pressure         reaching a predetermined limit.

The hydraulic crimper shown in FIGS. 1 to 15 in appearance resembles that of the earlier embodiment in that it has a handle 107 which may be held with the hydraulic crimper in balance. The forward end of the handle includes an actuator trigger 108 which can be reached by the thumb of a hand holding the crimper in balance.

The actuator 108 when it pivots pushes the rod 109 to change the settings of the control valve located in the rear of the handle 101, the rear of the handle forming a housing for the cartridge/spool 163 which is moved within the housing by the control rod to control hydraulic fluid flow as will be hereinafter described.

The rear handle 101 also forms a housing for the one way check valve comprising the check valve seat 119, ball 168 and spring 167. The check valve seat 119 forms the inlet for the hydraulic crimper. The check valve is arranged at the inlet to prevent damage should the hydraulic hoses be incorrectly attached to the device and to improve safety.

A relief valve 164 is also provided in the rear handle portion 101. The relief valve is arranged in association with the indicator/sensor 271 which comprises the components 114 to 118, 120, 157, 158, 165, 166, 173 and 174 listed in the integer list. These components are arranged in the manner suggested by the exploded view in FIG. 15 so as to create an indicator housing 114 separate from the hydraulic fluid. The housing contains an indicator in the form of a magnet which is moveable in response to the movement of the spring loaded pivotally mounted paddle 115. Because the paddle is arranged in line with fluid flow it moves in response to the pressure of fluid once it has passed through the pressure relief valve. Thus the magnet 165 fitted in the paddle 115 induces movement in the corresponding magnet/indicator 166 in the separate housing.

The rear handle 101 also includes a housing for the return valve 161 held in place by the bush 113 acts as a retaining plug. The bush forms a stop for a screw which can be used to adjust the setting of the valve.

The elongate crimping assembly 103 attached at the rear of the handle comprises a piston 102 which is slidable in a piston chamber closed by end cap 175.

The piston 102 is attached to the push rod 104 by screws 170. The piston seal 152 and O-ring seals 153, 154, and 156 are provided in locations to ensure the appropriate degree of pressure seal required. Screws 169 secure the end cap 175 to the section defining the bore 100.

A push rod 104 is provided in a bore formed as part of an elongate extension of the cap. A return spring 112 surrounds the push rod. The spring is arranged so as to urge the piston to the configuration shown in FIG. 12 in the absence of any countervailing hydraulic pressure.

The crimping head includes a die 106 shaped to receive an insert of chosen size for crimping connectors and lugs for electrical cables.

A moveable crimper head shoe 162 mounted via the crimper head base 105 on the push rod 104 is arranged to be moved towards and away from the die 106.

A stop 111 mounted by the screws 172 is provided to facilitate correct location of the crimping die 106.

Ducting is provided in the handle and crimping assembly for controlling the flow of hydraulic fluid to the piston chamber. The ducting will now be described with reference to FIGS. 16 to 21.

As in the case of the previous embodiment, the drawings illustrate an open centre and a closed centre valve setting according to the particular setting for valve 261.

Taking the case of FIGS. 16 to 18, the secondary valve 161 has been set in the open mode in that the secondary or return valve has been adjusted by means of the screw held in front of the bush 113 shown more clearly in FIG. 15 to a retracted position.

Thus, in a typical sequence of steps starting off with FIG. 16, the piston 102 begins in a position where it is in its rearward position. This is in effect a default position given the urging of the return spring 112 and the effect of hydraulic pressure when the actuator trigger is not depressed.

In this position, the control valve 274 is set so that hydraulic fluid entering the inlet 258 passes through the one way check valve 269 through the inlet duct 273 around the gallery formed around the valve spool into the second duct 243. As the forward piston chamber 280 is completely filled with hydraulic fluid and the piston 102 is at the most rearward part of its stroke, the build up of hydraulic fluid pressure in the duct 263 forces open the secondary valve 161. The secondary acts as a return valve. When the pressure reaches a predetermined limit, the valve opens and allows the fluid to flow through the outlet duct 262 and out the outlet 260.

Turning to FIG. 17, there is shown a configuration in which the actuator 108 has been depressed to push the push rod 109 inwards and reset the control valve in a configuration where the hydraulic crimper is activated. Thus, hydraulic fluid coming down the inlet duct 273 is diverted into the first duct 241 from whence it flows into the rear piston chamber 281.

The pressure of hydraulic fluid pushes the piston forward until it reaches its forward most point for crimping until it reaches its working pressure as set by the relief valve 245 and stops. As the piston moves forward the hydraulic fluid from the forward piston chamber 280 passes out through the second duct 243 via a bore through the centre of the spool of the control valve and out the duct 270.

As the pressure builds up due to the piston stopping at the crimping point, the pressure in duct 272, which is also in communication with duct 241 by virtue of the setting of the control valve, causes the relief valve 245 to open allowing the hydraulic fluid to flow into the indicator/sensor 271.

Movement of hydraulic fluid through the indicator 271 causes the paddle 115 with magnet 165 retained in the paddle to pivot. This in turn moves the magnet indicator 166 within its housing giving a visible indication that a correct crimp has been achieved by virtue of the fact that hydraulic fluid has flowed through the indicator/sensor 271. The hydraulic fluid then passes out through the outlet duct 262 and the outlet 260.

Referring to FIG. 19, in this instance, the return valve 161 has been closed by virtue of the fact that the screw in front of the retaining plug 113 has been screwed inwardly to its maximum extent. Thus, there is no flow of hydraulic fluid out of duct 263 when the actuator has not been pressed.

As the rear piston chamber is sealed by the piston, there is also no flow of hydraulic fluid out of the first duct 241 in this configuration. Thus there is no fluid flow in the crimper whilst it is in the not activated configuration as shown in FIG. 19 and there is no flow of hydraulic fluid out of the crimper outlet 260.

Referring to FIG. 21, after the actuator has been pressed, the piston moves forward and the crimper behaves in the same manner as has been described with reference to FIGS. 17 and 18 ie. the return valve 161 is bypassed via the relief valve 245 and associated duct 272 to allow hydraulic fluid to exit via the outlet duct 262 and outlet 260.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes of the steps, features, materials and other aspects referred to or indicated in this specification, individually or collectively and any and all combinations of any two or more of said steps or features.

It will be also understood that where the word “compromise”, and variations such as “comprises” and “comprising”, are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge in Australia.

Integer List

-   1 Hydraulic crimper -   3 Elongate crimping assembly -   5 Handle -   7 Actuator -   8 Pivot -   9 Die -   11 Crimping head -   13 Push rod -   14 Push rod -   15 Bore -   17 Connecting member -   19 Screw -   21 Piston -   23 Cylinder -   25 Piston housing -   26 Screw -   27 Bore -   29 Poppet valve -   30 Collar -   31 Ducting -   32 Ducting -   33 Screws -   34 Collar -   35 Gap -   37 Control valve -   39 Housing -   40 Chamber -   41 First Duct -   43 Second Duct -   45 Relief valve -   47 Housing -   49 Spool -   51 Gallery -   53 Opening -   54 Forward end -   55 Opening -   56 Opening -   59 Duct -   58 Inlet -   60 Outlet -   61 Collar -   62 Spring -   100 Bore -   101 Rear handle -   102 Piston -   103 Crimping assembly -   104 Push rod -   105 Crimper head base -   106 Die -   107 Handle -   108 Actuator trigger -   109 Rod -   110 Domed disc -   111 Stop -   112 Return spring -   113 Retaining plug -   114 Indicator housing -   115 Paddle -   116 Clear disc -   117 Paddle return spring -   118 Paddle base -   119 Check valve seat/inlet -   120 Paddle base pin -   121 C/-sunk socket head screw -   131 Bush -   132 Lip seal -   133 Shoe set screw -   134 Ball bearing -   135 Shoe keeper spring -   136 Shoe keeper -   137 Shoe press button -   138 Shoe press button pin -   139 Keeper spring -   140 Keeper -   141 Press button -   142 Press button pin -   143 Set screw -   151 Bearing -   152 Piston seal -   153 Rod seal -   154 O-ring -   155 O-ring -   156 O-ring -   157 O-ring -   158 Circlip -   159 Internal ring -   160 Oil gallery plug -   161 Return valve -   162 Crimper head shoe -   163 Cartridge/spool -   164 Relief valve -   165 Magnet -   166 Magnet -   167 Compression spring -   168 Ball -   169 Hexagon socket screw -   170 Hexagon socket screw -   171 Hexagon socket screw -   172 Hexagon socket screw -   173 Hexagon socket screw -   174 Washer -   175 Cap -   241 First duct -   243 Second duct -   245 Relief valve -   258 Inlet -   260 Outlet -   262 Outlet duct -   263 Duct -   269 Check valve/one way valve -   270 Duct -   271 Indicator/sensor -   272 Duct -   273 Inlet duct -   274 Control valve -   280 Forward piston chamber -   281 Rear piston chamber 

1. An hydraulic crimper comprising, an elongate crimping assembly with a forward end and a rearward end the crimper assembly having a crimping head moveable towards and away from a die, a handle for holding the crimping assembly, the handle extending above the crimping assembly and being constructed so that it has a balanced position where it may be held with the hydraulic crimper in balance, an actuator moveable between an on setting and an off setting, the actuator being located on the handle, a control valve for controlling flow of hydraulic fluid under pressure to move the crimping head, and a mechanical linkage extending from the actuator to the control valve whereby to control the movement of the crimping head in response to the setting of the actuator.
 2. An hydraulic crimper according to claim 1 wherein the crimping assembly comprises, a piston chamber near the rearward end of the crimping assembly, a piston slidable within the piston chamber in response to pressure from the hydraulic fluid, and a first push rod connecting the crimping head and piston.
 3. An hydraulic crimper according to claim 1 wherein, one end of the handle is connected to the rearward end of the crimping assembly, the actuator comprises a pivotable member operable by finger or thumb pressure, and the pivotable member is located at a position on the handle forward of the balanced position whereby an operator may hold the handle in one hand at the balanced position whilst being able to push the pivotable member with a finger or thumb of the one hand.
 4. An hydraulic crimper according to claim 2 wherein, a forward part of the piston chamber is spaced from a rearward part of the piston chamber by the piston, an inlet is arranged to direct the hydraulic fluid to the control valve, and the control valve is arranged to direct the hydraulic fluid to the rearward part of the piston chamber when the actuator assumes the on setting and to the forward part of the piston chamber when the actuator assumes the off setting.
 5. An hydraulic crimper according to claim 4 comprising, an outlet for the hydraulic fluid, a secondary valve which is adapted to be set in an open configuration and a closed configuration, wherein the secondary valve is arranged to allow the hydraulic fluid under pressure to flow through the secondary valve and out of the outlet when the secondary valve is set in the open configuration and to prevent the hydraulic fluid under pressure flowing through the secondary valve and out of the outlet when it is in the closed configuration.
 6. An hydraulic crimper according to claim 5 wherein the control valve and secondary valve are located in a rearward section of the handle.
 7. An hydraulic crimper according to claim 6 comprising, a first duct for allowing the hydraulic fluid to flow from a primary outlet of the control valve to the rearward part of the piston chamber, a second duct for allowing the hydraulic fluid to flow from a secondary outlet of the control valve to the forward part of the piston chamber, a bypass duct in communication with the second duct and with the outlet, wherein the secondary valve is arranged to control the flow of the hydraulic fluid through the bypass duct.
 8. An hydraulic crimper according to claim 7 wherein the control valve comprises, a housing provided in the handle, and a spool moveable within the housing.
 9. An hydraulic crimper according to claim 1 comprising, an outlet duct for directing the hydraulic fluid from the control valve to an outlet from the hydraulic crimper, and a pressure sensitive relief valve set to open and allow the hydraulic fluid to pass through the outlet duct when the pressure in the outlet duct exceeds a predetermined limit and to close and block the passage of the hydraulic fluid through the outlet duct when the pressure of the hydraulic fluid is below the predetermined limit.
 10. An hydraulic crimper according to claim 9 comprising, a sensor set to signal the passage of the hydraulic fluid through the outlet duct downstream of the pressure sensitive relief valve.
 11. An hydraulic crimper according to claim 1 including retraction means for automatically retracting the crimping head away from the die when pressure of the hydraulic fluid drops below a predetermined limit.
 12. An hydraulic crimper comprising, an elongate crimping assembly with a forward end and rearward end the crimper assembly having a crimping head moveable towards and away from a die, an actuator moveable between an on setting and an off setting, a control valve for controlling flow of the hydraulic fluid under pressure to move the crimping head, a mechanical linkage extending from the actuator to the control valve whereby to control the movement of the crimping head in response to the setting of the actuator; and retraction means adapted to automatically retract the crimping head away from the die when the pressure of the hydraulic fluid falls below a predetermined limit.
 13. An hydraulic crimper according to claim 12 wherein the crimping assembly comprises, a piston chamber near the rearward end of the crimping assembly, a piston slidable within the piston chamber in response to pressure from the hydraulic fluid, and a first push rod connecting the crimping head and piston.
 14. An hydraulic crimper according to claim 13 wherein the retraction means comprise a spring telescoping the first push rod.
 15. An hydraulic crimper according to claim 12 comprising a handle for holding the crimping assembly, the handle extending above the crimping assembly and being constructed so that it has a balanced position where it may be held with the hydraulic crimper in balance, and wherein, one end of the handle is connected to the rearward end of the crimping assembly, the actuator comprises a pivotable member operable by finger or thumb pressure, and the pivotable member is located at a position on the handle forward of the balanced position whereby an operator may hold the handle in one hand at the balanced position whilst being able to push the pivotable member with a finger or thumb of the one hand.
 16. An hydraulic crimper according to claim 13 wherein, a forward part of the piston chamber is spaced from a rearward part of the piston chamber by the piston, an inlet is arranged to direct the hydraulic fluid to the control valve, and the control valve is arranged to direct the hydraulic fluid to the rearward part of the piston chamber when the actuator assumes the on setting and to the forward part of the piston chamber when the actuator assumes the off setting.
 17. An hydraulic crimper according to claim 16 comprising, an outlet for the hydraulic fluid, a secondary valve which is adapted to be set in an open configuration and a closed configuration, wherein the secondary valve is arranged to allow the hydraulic fluid under pressure to flow through the secondary valve and out of the outlet when the secondary valve is set in the open configuration and to prevent the hydraulic fluid under pressure flowing through the secondary valve and out of the outlet when it is in the closed configuration.
 18. An hydraulic crimper according to claim 17 wherein the control valve and secondary valve are located in a rearward section of the handle.
 19. An hydraulic crimper according to claim 18, comprising, a first duct for allowing the hydraulic fluid to flow from a primary outlet of the control valve to the rearward part of the piston chamber, a second duct for allowing the hydraulic fluid to flow from a secondary outlet of the control chamber to the forward part of the piston chamber, a bypass duct in communication with the second duct and with the outlet, wherein the secondary valve is arranged to control the flow of the hydraulic fluid through the bypass duct.
 20. An hydraulic crimper according to claim 19 wherein the control valve comprises, a housing provided in the handle, and a spool moveable within the housing.
 21. An hydraulic crimper according to claim 12 comprising, an outlet duct for directing the hydraulic fluid from the control valve to an outlet from the hydraulic crimper, and a pressure sensitive relief valve set to open and allow the hydraulic fluid to pass through the outlet duct when the pressure in the outlet duct exceeds a predetermined limit and to close and block passage of the hydraulic fluid through the outlet duct when the pressure of the hydraulic fluid is below the predetermined limit.
 22. An hydraulic crimper according to claim 21, comprising, a sensor set to signal passage of the hydraulic fluid through the outlet duct downstream of the pressure sensitive relief valve.
 23. A sensor for signalling the passage of the hydraulic fluid through a duct comprising, a flow member exposed to the movement of the hydraulic fluid through the duct moveable in response to movement of the hydraulic fluid through the duct, and sensing means isolated from contact with the hydraulic fluid, the sensing means being responsive to movement of the flow member to provide a signal for indicating the passage of the hydraulic fluid.
 24. A sensor according to claim 23 wherein the flow member comprises a paddle mounted for pivotal movement in response to the passage of the hydraulic fluid through the duct and the sensing means comprise a chamber for housing and isolating a moveable, visible indicator member from the hydraulic fluid, and at least one of the paddle and visible indicator include a permanent magnet to magnetically tie the movement of the visible indicator to respond to movement of the paddle.
 25. A sensor according to claim 24 wherein the chamber includes a transparent window through which the visible indicator may be viewed and the paddle is connected to resilient means to urge the paddle to a rest position in the absence of the hydraulic fluid moving through the duct.
 26. An hydraulic crimper comprising, an elongate crimping assembly with a forward end and a rearward end the crimper assembly having a crimping head moveable towards and away from a die, an inlet for hydraulic fluid, an actuator moveable between an on setting and an off setting, a control valve for controlling flow of hydraulic fluid under pressure to move the crimping head, a mechanical linkage extending from the actuator to the control valve whereby to control the movement of the crimping head in response to the setting of the actuator, an outlet for the hydraulic fluid, an outlet duct for allowing communication between the control valve and the outlet, and a sensor according to claim 23 arranged to signal the passage of the hydraulic fluid through the outlet duct.
 27. A hydraulic crimper according to claim 26 comprising, a handle for holding the crimping assembly, the handle extending above the crimping assembly and being constructed so that it has a balanced position where it may be held with the hydraulic crimper in balance, the actuator being located on the handle, a piston chamber near the rearward end of the crimping assembly, a piston slidable within the piston chamber in response to the hydraulic fluid pressure, and a first push rod connecting the crimping head and piston.
 28. An hydraulic crimper according to claim 27, wherein, one end of the handle is connected to the rearward end of the crimping assembly, the actuator comprises a pivotable member operable by finger or thumb pressure, and the pivotable member is located at a position on the handle forward of the balanced position whereby an operator may hold the handle in one hand at the balanced position whilst being able to push the pivotable member with a finger or thumb of the one hand.
 29. An hydraulic crimper according to claim 27 wherein, a forward part of the piston chamber is spaced from a rearward part of the piston chamber by the piston, an inlet is arranged to direct the hydraulic fluid to the control valve, and the control valve is arranged to direct the hydraulic fluid to the rearward part of the piston chamber when the actuator assumes the on setting and to the forward part of the piston chamber when the actuator assumes the off setting.
 30. An hydraulic crimper according to claim 29 comprising, an outlet for the hydraulic fluid, a secondary valve which is adapted to be set in an open configuration and a closed configuration, wherein the secondary valve is arranged to allow the hydraulic fluid under pressure to flow through the secondary valve and out of the outlet when the secondary valve is set in the open configuration an to prevent the hydraulic fluid under pressure flowing through the secondary valve and out of the outlet when it is in the closed configuration.
 31. An hydraulic crimper according to claim 29 wherein the control valve and secondary valve are located in a rearward section of the handle.
 32. An hydraulic crimper according to claim 31, comprising, a first duct for allowing the hydraulic fluid to flow from a primary outlet of the control valve to the rearward part of the piston chamber, a second duct for allowing the hydraulic fluid to flow from a secondary outlet of the control chamber to the forward part of the piston chamber, a bypass duct in communication with the second duct and with the outlet, wherein the secondary valve is arranged to control the flow of the hydraulic fluid through the bypass duct.
 33. An hydraulic crimper comprising, an elongate crimping assembly with a forward end and rearward end the crimper assembly having a crimping head moveable towards and away from a die, an actuator moveable between an on setting and an off setting, a control valve for controlling flow of hydraulic fluid under pressure to move the crimping head, an inlet for the hydraulic fluid, an outlet for the hydraulic fluid, a mechanical linkage extending from the actuator to the control valve whereby to control the movement of the crimping head in response to the setting of the actuator, an outlet duct for directing the hydraulic fluid from the control valve to the outlet, and a one way valve set to open and allow the hydraulic fluid to pass through the inlet so as to provide a one way flow direction of hydraulic fluid from the inlet to the outlet and to prevent flow in the reverse direction.
 35. A hydraulic crimper according to claim 33 comprising, a handle for holding the crimping assembly, the handle extending above the crimping assembly and being constructed so that it has a balanced position where it may be held with the hydraulic crimper in balance, the actuator being located on the handle, a piston chamber near the rearward end of the crimping assembly, piston slidable within the piston chamber in response to the hydraulic pressure, and a first push rod connecting the crimping head and piston.
 35. An hydraulic crimper according to claim 34 wherein, one end of the handle is connected the rearward end of the crimping assembly, t he actuator comprises a pivotable member operable by finger or thumb pressure, and the pivotable member is located at a position on the handle forward of the balanced position whereby an operator may hold the hydraulic crimper handle in one hand at the balanced position whilst being able to push the pivotable member with a finger or thumb of the one hand.
 36. An hydraulic crimper according to claim 34 wherein, a forward part of the piston chamber is spaced from a rearward part of the piston chamber by the piston, an inlet is arranged to direct the hydraulic fluid to the control valve, and the control valve is arranged to direct the hydraulic fluid to the rearward part of the piston chamber when the actuator assumes the on setting and to the forward part of the piston chamber when the actuator assumes the off setting.
 37. An hydraulic crimper according to claim 36 comprising, an outlet for the hydraulic fluid, a secondary valve which is adapted to be set in an open configuration and a closed configuration, wherein the secondary valve is arranged to allow the hydraulic fluid under pressure to flow through the secondary valve and out of the outlet when the secondary valve is set in the open configuration and to prevent the hydraulic fluid under pressure flowing through the secondary valve and out of the outlet when it is in the closed configuration.
 38. An hydraulic crimper according to claim 32 wherein the control valve and secondary valve are located in a rearward section of the handle.
 39. An hydraulic crimper according to claim 38 comprising, a first duct for allowing the hydraulic fluid to flow from a primary outlet of the control valve to the rearward part of the piston chamber, p1 a second duct for allowing the hydraulic fluid to flow from a secondary outlet of the control chamber to the forward part of the piston chamber, a bypass duct in communication with the second duct and with the outlet, wherein the secondary valve is arranged to control the flow of the hydraulic fluid through the bypass duct.
 40. An hydraulic crimper according to claim 39 wherein the control valve comprises, a housing provided in the handle,.and a spool moveable within the housing. 